The goal of this proposal is to develop and evaluate a patient-mounted MRI-compatible shoulder arthrography robot integrated with a sensitive MRI imaging coil. The patient-mounted robot is intended to enable a novel workflow for pediatric arthrography that eliminates the need for fluoroscopy while providing accurate image-guided needle placement in the MRI suite. This proposal is a first step toward achieving our long-term goal of offering MRI-guided, radiation-free procedures to pediatric patients. MRI scanning is the standard of care for musculoskeletal imaging and therefore musculoskeletal injuries are well suited to MRI-guided interventions. While this proposal is focused on pediatrics, the techniques developed here will be applicable to adult procedures as well. In this project, we will develop a novel, custom-designed coil array that will fit inside the base of our MRI- compatible robot and enable high-resolution imaging of the shoulder joint during needle-based interventions. For the arthrography procedure, the coil array and robot will enable us to complete the procedure in the MRI suite in one setting and eliminate the need for fluoroscopy. This is particularly significant i the pediatric setting since there are increasing concerns about the long-term consequences of radiation exposure in children. Our specific aims are to: 1. Design, construct, and test an MRI coil array that can fit inside the base of the MRI compatible robot developed at Children's National Medical Center. The coil array will be constructed using a novel integrated balun approach that has a low-profile and is insensitive to radiofrequency field disturbances caused by nearby conducting structures such as cables and wires. 2. Modify the prototype body-mounted robot to accommodate the new coil array. These modifications will include improvements to the robot design, changing the robot base for the coil to fit, and including fiducials for registration purposes. 3. Test the targeting accuracy of the integrated system in the MRI suite in a mock-up study and with anthropomorphic and ham phantoms. Make design improvements required and repeat the evaluations.